How to know is your Android device official or not:
There are two ways to find out is your device Officially running on Android or not.
Turn your android device ON and go into Apps or open settings.
Press the left side just beside the home button on the bottom of your screen
If you find it difficult, select Apps from your home screen
Now you need to look for Settings icon. Depending upon the number of applications installed it will be on some screen. Just swipe the screens until you find Settings App
Under settings click on More icon as shown in the picture below:
Select About device present in bottom of the screen as shown below
Now Select Status as shown below:
Under Status èScroll down to the bottom of the page and the last option which is device status, will let you know is your device official or not.
Switch off the Galaxy Note 2. Place the phone in Download Mode by pressing and holding Volume Down + Home button & Power buttons together until a construction Android robot icon with a warning triangle appears on screen.
Now press the Volume Up button to enter continue to enter into Download Mode
You will be presented here with all the information about your device.
Due to the above blurred image the red sentence is Odin Mode
Below that you will have
Custom Binary Download:
Current Binary: Samsung Official
System Status: Official
Warranty Void: 0
Under System Status it should say Official if your rom is stock